The invention relates to a valve control device with the features of the generic part of Patent Claim 1 and a drive device which can in particular be used for the valve control device.
Such valve control devices are for example employed with so-called control pods or similar equipment in the mining and/or production of mineral oil/natural gas Such a control pod can for example be arranged on the sea bed and is used at the point of application with a range of valve control devices for the adjustment, actuation and control of valves, throttles, blowout preventers and other equipment.
A suitable valve control device exhibits a valve housing in which various hole sections are arranged. Relative to these hole sections a valve slide with at least a first and a second flow hole is movably supported inside the valve housing. The valve slide is in each case displaced with the flow holes such that the corresponding flow holes complement the hole sections for the flow of an appropriate fluid or, if an appropriate flow hole is not aligned to the hole sections, the flow through these hole sections is interrupted. If the hole sections are complemented by a flow hole, then a connection can alternatively be made by it between a feed line of a fluid pressure source to at least one actuator or between an actuator to a return line for leading the fluid away.
In the first case the fluid is fed to the actuator, whereby it for example actuates a valve, throttle, blowout preventer or similar device. If this actuation is to be interrupted, the fluid which is under pressure is routed through the appropriate flow hole from the actuator to the return line by displacement of the valve slide into another position and by connecting other hole sections.
Appropriate to the number of hole sections, flow holes and return and feed lines, various valve control devices can be realised, such as for example 2/2, 3/2, 4/2, 4/3, 5/2, 5/3 directional control valves or similar devices.
With such a known valve control device the sealing of the hole sections not connected by means of a flow hole occurs by the valve slide itself and appropriate sealing elements between the slide, the hole sections and the valve housing. With such valve control devices it has however been found that especially with the often very high pressures required, particularly in the field of mineral/natural gas mining or production, a leakage flow of the pressure fluid in the respective valve control device with the valve slide in the closed position cannot be neglected. Since generally, many such valve control devices in one control pod or also many control pods with a large number of valve control devices are employed at the point of application, a serious problem arises with regard to the replenishment of pressure fluid as well as regarding contamination of the environment.